Johnson Screens manufactures a complete line of Vee-Wire stainless steel and PVC well screens, slotted PVC screens, PVC drop pipe, casings and accessories.
In my last column, I wrote about developing well screens in cable tool drilled wells and here are a couple more, including perhaps the two most popular methods.
In my last several columns, I discussed selecting a screen for our water well and some installation methods. Having our screen installed, we move onto the next step in constructing a good water well: developing the well and the formation around the well screen.
In my last several columns, I have written about selecting the proper openings for a water well screen and some popular installation methods. One thing we must do, however, before installing the screen is equip it with the proper fittings. Screens purchased from a manufacturer or supply house are not going to work as is (with a couple of exceptions).
In my last column, I talked at some length about selecting screen openings and then ended up by describing one installation method: just driving a pointed screen into a water-bearing formation. Now, I am aware that in this day and age many screens are either threaded or glued directly to the bottom of the casing in a rotary hole. This certainly works, but if the screen has the wrong openings or fails for some other reason either at installation or later, it is impossible to pull. I’m going to limit my comments to screens that can be pulled and would be used in a cable tool or hollow rod drilled well.
Drillers know they make an impact, but that doesn’t usually mean helping to supply water for hundreds of thousands of people. Steven Bryan sensed the scope of the Central Utah Water Conservancy District project when he got the call. Working the project, which involves several 24-inch wells that will supply a swath of central Utah, only confirmed the impact.
At the end of my last column, I had discussed how to do a graduated sieve analysis of a sand and gravel aquifer and hinted at how we might select our screen openings from this. As you will recall, I described how we could plot the analysis of our formation on graph paper with slot openings or grain size in thousandths of an inch on the horizontal scale with zero at the far left. The vertical scale will list cumulative percent retained from zero at the bottom to 100 at the top. If we plot what our graduated sieves have retained, we will develop an S curve or we can simply connect the dots as a child might do.
Having discussed my experience with different well screen designs in former columns, if you get the idea I’m a proponent of stainless steel or bronze wire wound screens, you are right. Actually, I’m not sure bronze or brass screens are available anymore. I have not seen a new one in a lot of years. In my opinion, that is OK. Stainless steel works very well, at least in the waters we encounter here in the Midwest.
The deck I discussed last month is looking good although the boards have shrunk a little bit—it’s OK, though. It is time to get back to our discussion of well screens.
